This invention relates to a conveyor unit for a device for harvesting long agricultural products, such as grass, straw, pulses, biomass products and the like, and a harvesting device which uses said unit.
Harvesting devices are normally used for harvesting from the ground grass, straw, hay (cut by other machines) or for harvesting pulses; in any case for harvesting similar agricultural products (usually plants), with a long shape.
For that purpose they are connected to a pulling vehicle (such as a tractor or a self-propelled agricultural machine) and moved by it.
The prior art harvesting devices have a preferred axis of extension which, during use, remains transversal to the axis of movement of the pulling vehicle and, to lift off the ground and move (before unloading) the agricultural products, said harvesting devices use a plurality of harvesting elements associated with them and which are moved by a movement system. The movement system is usually driven by a universal joint or the like which, by means of a power take-off, takes driving power from the engine of the pulling vehicle.
Each harvesting element is, in turn, equipped with one or more prongs arranged side by side. The harvesting elements (and the related prongs) are usually positioned around the preferred axis of extension along rows parallel with the preferred axis of extension. Each harvesting element (and the related prongs) is moved by the movement system along a closed trajectory surrounding the preferred axis of extension. The prongs are straight elements with one end hooked (directly or by means of parts of the related harvesting element) to the movement system, whilst the opposite end is free.
Moreover, operatively downstream of the harvesting elements, the devices may comprise means for unloading the agricultural products harvested, such as windrowers, presses, silage cutters or conditioners.
Such unloading means are usually movement devices such as conveyor belts, chains or screw feeders positioned along the axis of extension of the harvesting device and positioned at a harvesting element product release point to allow the products to be conveyed to the sides of the pulling vehicle, or to the centre.
Alternatively, operatively downstream of the harvesting elements there could be an operating machine, such as a baler, a cutter or a chamber for receiving the agricultural products harvested.
Disadvantageously, the prior art devices have critical points both relating to the transit of the products exiting the harvesting elements and relating to the cleanness of said transit zone.
In fact, it is often the case that the agricultural products, once released by the harvesting elements, are not immediately channelled onto the unloading means, but remain in the transit zone, getting jammed and causing a gradual deterioration in device performance.